In:
Arteriosclerosis, Thrombosis, and Vascular Biology, Ovid Technologies (Wolters Kluwer Health), Vol. 17, No. 10 ( 1997-10), p. 2010-2019
Abstract:
Abstract We investigated the contribution of apoE to cholesterol efflux into plasmas of normal, apoA-I-, and apoE-deficient mice, which were fed with chow- and cholesterol-rich diets. Plasmas of normal and apoA-I-deficient mice contain apoE in pre-β-migrating VLDL as well as in HDL-like lipoproteins, which have either electrophoretic α- or γ-mobilities. The latter particle resembled γ-LpE in human plasma also by its mobility on nondenaturing two-dimensional electrophoresis. No apoE-containing lipoproteins were found in plasmas of apoE-deficient mice. When apoA-I- and apoE-deficient mice received both chow- and fat-rich diets, their plasmas released significantly less 3 H-cholesterol from radiolabeled fibroblasts than did plasma of normal mice. Removal of apoE from plasmas of normal and apoA-I-deficient mice by anti-apoE immunoaffinity chromatography decreased their cholesterol efflux capacities (per 1 minute/per 1 hour) by 26%/40% ( P =0.0092/0.0007) and 30%/26% ( P =0.0092/0.0003), respectively. Net cholesterol efflux from fibroblasts into apoA-I-deficient plasma was 45% lower compared with plasma of normal mice. Incubation of fibroblasts with apoE-deficient plasma caused net influx of cholesterol. Prior addition of human apoE to or removal of apoB-containing lipoproteins from apoE-deficient plasma restored its ability to cause net cholesterol efflux to 50% of normal plasma. Some of the differences between cholesterol efflux into normal and apoE-deficient plasmas were attributable to the failure of apoE-deficient plasmas to take up cell-derived 3 H-cholesterol into γ-LpE. Compared with normal plasma, both apoA-I-deficient and apoE-deficient plasmas were significantly decreased in their activity to esterify cell-derived 3 H-cholesterol. Anti-apoE chromatography decreased significantly cholesterol esterification in normal plasma and apoA-I-deficient plasma but not in apoE-deficient plasma. Taken together, the data provide evidence that apoE is an important contributor to reverse cholesterol transport, partially because of initial uptake of cell-derived cholesterol by γ-LpE and partially because of the contribution of apoE-containing lipoproteins to esterification of cholesterol in plasma.
Type of Medium:
Online Resource
ISSN:
1079-5642
,
1524-4636
DOI:
10.1161/01.ATV.17.10.2010
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
1997
detail.hit.zdb_id:
1494427-3
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